EZ80F91MCU ZILOG [Zilog, Inc.], EZ80F91MCU Datasheet - Page 185

• Manufacturer Part Number: EZ80F91MCU
• Description: eZ80Acclaim-TM Flash Microcontrollers
• Manufacturer: ZILOG [Zilog, Inc.]

Real-Time Clock
Figure 34. Real-Time Clock and 32KHz Oscillator Block Diagram
PS019209-0504
System Clock
Real-Time Clock Overview
The Real-Time Clock (RTC) keeps time by maintaining a count of seconds, min-
utes, hours, day-of-the-week, day-of-the-month, year, and century. The current
time is kept in 24-hour format. The format for all count and alarm registers is
selectable between binary and binary-coded-decimal (BCD) operations. The cal-
endar operation maintains the correct day of the month and automatically com-
pensates for leap year. A simplified block diagram of the RTC and the associated
on-chip, low-power, 32 KHz oscillator is illustrated in Figure 34. Connections to an
external battery supply and 32 KHz crystal network are also demonstrated in
Figure 34.
IRQ
ADDR[15:0]
DATA[7:0]
Real-Time Clock
V
RTC Clock
DD
(RTC_CTRL[4])
CLK_SEL
P R E L I M I N A R Y
Enable
V
DD
Low-Power
32 KHz Oscillator
RTC_X
RTC_X
RTC_V
DD
OUT
IN
32 KHz
Crystal
R1
Product Specification
Battery
eZ80F91 MCU
Real-Time Clock
C
C
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